40K on Under Drive pulley.

I put it on at 90k, changed the original belt at 100K and noticed it wearing in but it was very very little. Just changed the original water pump and pulleys today at 130k. I put the original pulley back on because it's one of those things I don't wanna risk on the wife's car in Alaska. It's a good thing I saved the original pulley and ran A/C compressor spacers to keep the original belt. I have 2 10's in the trunk and the volts always drop after running a few minutes at idle with the heater on high and every once in a while Metallica kills the radio at stop lights so it's time to put Lola back to stock.

http://i47.photobucket.com/albums/f1...psfokcwfls.jpg

http://i47.photobucket.com/albums/f1...ps7yw4iqvt.jpg

http://i47.photobucket.com/albums/f1...psclseslvd.jpg